Anchorage for multiple strand cables



out. 31,- 1939. s, MOISSEiFF ET AL 2,178,147

ANCHORAGE FOR MULTIPLE STRAND CABLES Filed Jan. 18, 1957 2 Sheets-Sheet 1 INVENTORS LEO/v SMO/SSE/FP fkmL-RICKLIENHARD BY r I i a a W TTQRP- EY' och L. s. MOISSEIFF ET AL 117 ANCHORAGE FOR MULTIPLE STRAND CABLES Filed Jan. 18, 1937 2 Sheets-Sheet 2 Patented Oct. 31, 1939 umran STATES PATENT OFFIQE.

ANCHORAGE FOR MULTIPLE STRAND CABLES poration of New York Application January 18,

13 Claims.

The present invention relates to an improved anchorage for a multiple strand cable in which provision is made for anchoring and adjusting the tension of each strand individually.

The invention is particularly adapted for anchoring bridge cables, although manifestly, the anchorage could also be used for cables adapted for other purposes. Furthermore, the invention is also adapted for use in anchoring individual wires of strands or cables.

In building suspension bridges of comparatively short span it is desirable to make up the cables of preformed strands cut to uniform length and provided with end fittings in the factory. However, each strand must be individually tensioned to be sure that it will carry its full share of the load. While in the main body of the cable the strands are compactly bundled together they must be splayed out at the anchorage to provide room for the end fittings and for the tensioning and anchoring means.

An object of the present invention is to provide a very simple and compact anchorage in which the splay angle will be reduced to a minimum, thereby keeping the maximum bend in any strand well within its elastic limits.

A further object of the invention is to provide an anchorage in which the parts will be readily accessible for tensioning the strands in such sequence as to prevent skewing and unbalanced strains. In order to accomplish this result it is desirable to arrange the strands in vertically spaced horizontal tiers and in anchoring the strands it is desirable to start with bottom tiers, to tension first the strands which lie directly on the saddle of the bridge tower, after which the other tiers may be progressively tensioned and anchored. In each tier it is preferable to tension the middle strand or strands first and thereafter to tension the strands at each side thereof, thereby maintaining a proper balance. The present invention has for an object to provide an anchorage in which such order of procedure may be conveniently carried out.

Other objects and advantages of the invention will appear in the following description of a preferred embodiment and thereafter the novelty and scope of the invention will be pointed out in the claims. I

In the accompanying drawings Figure l is a view in side elevation of the improved anchorage with a concrete abutment of the anchorage indicated fragmentally and in section;

Fig. 2 is a view in cross section on a larger 1937, Serial No. 121,157

scale, the section being taken on the line 2-2 of Fig. 1;

Fig. 3 is a view in cross section and on a larger scale, the section being taken on line 3-3 of Fig. 1;

Fig. 4 is a view in side elevation and partly in section showing certain details of the anchorage, the section being taken on the line 44 of Fig. 5;

Fig. 5 is a plan view partly broken away and showing a portion of the bottom tier of anchorage elements embraced within the lines 5-5 of Fig. l; and

Fig. 6 is a similar plan view of the middle tier of anchorage elements showing that portion thereof embraced within the lines 66 of Fig. 1.

The cable l8, illustrated in the drawings, is made up of nineteen strands H, as clearly shown in Fig. 3. Obviously, the number of strands may be varied as desired and the anchorage correspondingly modified. The strands are nested together in the main body of the cable, as shown in Fig. 3, and are passed through a splay casting it which is suitably grooved to conform to the outer contour of the cable. These grooves are gradually flared toward the anchorage topermit the requisite splaying of the strands.

The strands adjacent the anchorage are grouped in five vertically spaced rows, as shown in Fig. 2, the middle row comprising three strands and the others four each. strands are maintained in mutually spaced relation by means of a spreader consisting of a pair of bars i i and which are grooved on their adjacent faces to fit about the strands and the bars are clamped together by means of bolts 16.

Each strand is provided with an end fitting 58. It will be understood that the strands are cut to length in the factory, passed through the splay casting i2, and then provided with the end fittings. Each end fitting comprises a socket portion 28 which is tapered and in which the strand is permanently fixed by means well known in the art, as, for instance, by brooming the end of the strand and embedding the same in a mass of solder or other suitable metal. Projecting axially toward the anchorage from each socket member is a shank 2! which terminates at its free end in a hook 22. Passing through the sides of the shank is a slot 23 elongated in the direction of the longitudinal axis of the fitting and formed at its outer end with an end face 24 normal to said axis.

The anchorage comprises an abutment 25 of masonry or concrete in which are embedded two girders 26, only one of which is shown in the In each row the drawings. Each girder is of T-section and bolted or otherwise secured to the central web of the T are five pairs of anchor bars 21, the members of each pair being disposed respectively at opposite sides of said web. Thus, there will be two pairs of bars 21 for each tier of strands, as shown in Fig. 5. The outer ends of these bars 21 project from the face of the abutment and are apertured to receive a transverse pin 29. girders 26 are spaced farther apart than the projecting ends of the anchor bars and consequently the bars toe inwardly toward the pin. Accordingly, a sleeve 30 with tapered end faces is used as a spacer between the two inner bars 21 of each tier. Wedge-shaped washers 3| bear against the outer sides of these inner bars and provide outer faces normal to the axis of the pin 29. Pivotally mounted on the pin 29 and bearing against said faces are two parallel links 32 to which the individual strands of a tier of strands are to be secured, as will be explained hereinafter. Wedge-shaped washers 35 are fitted between the links 32 and the outer bars 21 of each tier and wedge-shaped washers 36 bear against the outer faces of the outer bars 21. The parts are clamped together by means of a bolt 31 passing axially through the pin 29 and bearing at opposite ends thereof against the washers 38. Since the strands which are to be attached to the links are splayed from a common casting 12, the tiers of bars 21 preferably lie in planes radiating from the splay casing l2 as a center, and the bars are adjusted as to length so that the pins 29 will lie substantially on an arc struck from the splay casting as a center.

Each pair of links 32 is apertured at its outer end to receive a transverse pin 40. This pin passes through the slots 23 of the end fittings [8. Each link is formed with a hole 42 adjacent the anchorage bars through which a pin 53 may be passed to engage a hook 45 on one end of a hydraulic jack 46, or other tensioning means. The plunger of the hydraulic jack is provided with a bifurcated hook 41 adapted to embrace the hook 22 of the strand that is to be tensioned and the hooks are interconnected by inserting a pin 48 between them, as shown in Fig. l. The jack may then be operated to pull the strand to the desired tension and in this tensioned condition the strand is held by inserting a filler block 50 and the requisite number of shims 5| between the pin and the end face 24 of slot 23. The block 50 is formed with a recess contoured to fit the adjacent side of the pin 40.

As shown in Fig. 5, where four strands are provided in a tier, two of the end fittings are disposed between the links 3?. and the other two at the outer sides of the links respectively. Washers 53 and 54 are provided on opposite sides of each link 32 to space the end fittings of the middle from the fittings of the outer strands, and a collar 55 is mounted on the pin between the two middle strands of the tier. The collar is made in halves bolted together, as indicated at 56, so that it may be fitted upon the pin 40 after the other parts have been assembled thereon. A bolt 51 passes axially through the pin 40 and bears against washers 58 at opposite ends of the pin, thus providing means for clamping the parts securely in place. In the case of the three strand tier a similar construction is employed except that a wide collar 69 takes the place of one of the washers 53 and a wide split collar 6| takes the place of the split collar 55.

In assembling the parts the lower tier of Preferably the.

strands is first anchored because these are the strands that lie on the bottom of the saddle of the bridge tower. Since the links 32 are pivoted on the pins 29, all but the bottom tier of links may be swung while the strands of the bottom tier are tensioned and anchored. First the two middle strands of this tier are tensioned. The fittings [8 of these strands are mounted on the pin 40 with the washers 53 in place, but with the collar 55 removed. The hydraulic jack 46 is connected first to one of the two middle end fixtures and after this has been pulled to the desired tension a filler block is inserted laterally into the slot 23, after which shims 5| are inserted to make a tight fit between the pin 40 and the end wall 24 of the slot 23. With the collar out of the way there is ample space to permit of introducing the block 50 and shims 5|. After one of the middle strands has been properly tensioned and anchored the other one is similarly tensioned, blocked and shimmed. Then the collar 55 is applied to keep the blocks and shims from lateral displacement. Finally, the fixtures [8 of the outer strands of the tier are similarly tensioned, blocked and shimmed after which the bolt 51 and washers 58 are applied to clamp all the parts in place. While tensioning the strands the bolts IS on the Spreaders may be eased to permit the strands to slide therethrough, but after the tension has been completed these bolts are tightened.

Work now proceeds on the next tier above and so on until the entire set of strands has been tensioned and suitably anchored. The operation on the middle tier is similar to that on any of the other tiers, the only difference being that a wide collar 60 is used on one side of the central end fitting and a broad collar 6| on the other side, the latter collar being removed during the tensioning step to permit of introducing the block 50 and shims 5|, after which the collar is applied and bolted in place.

While we have described a preferred embodiment of our invention it will be understood that this is to be taken as illustrative and not limitative and that we reserve the right to make various changes in form, construction and arrangement of parts without departing from the spirit and scope of our invention as set forth inthe claims.

We claim:

1. In a supporting element for a suspension bridge, a cable comprising a plurality of strands diverging from a common point, a fitting on the end of each strand provided with an elongated slot, a plurality of links arranged in tiers, the links of each tier being provided near their ends with aligned holes, a pivot pin passing through the aligned holes in the links of each tier and also through the elongated slots of certain of said fittings, and a spreader located between the common point of divergence of the strands and the pin of each tier and adapted to so space the strands of said tier that those portions of the strands between the spreader and the pin are in substantial parallelism.

2. In a supporting element for a suspension bridge, a cable comprising a plurality of strands diverging from. a common point, a fitting on the end of each strand provided with an elongated slot, a plurality of links arranged in tiers, the links of each tier being provided near their ends with aligned holes, a pivot pin passing through the aligned holes in the links of each tier and also through the elongated slots of certain of said fittings, a spreader located between the common point of'divergence of the strands and the pin of each'tier and adapted to so space the strands of said tier that those portions of the strands between the spreader; and the pin arein substantial parallelism, inserts' in the slots fitted between'the pin and the outer end wall of each slot,'and means for clamping all of the fittings in said tier in mutually spaced relation on the pin including annular spacing members on'the pin and overlapping the inserts.

3- In a supportingelement for a suspension bridge, a cable comprising a plurality of strands diverging from a common point, a fitting on the end of each strand provided with an elongated slot, a plurality of links arranged in tiers, the links of each tier being provided near their ends with aligned'holes, a pivot pin passing through the aligned holes in the links of each tier and also through the elongated'slots of certain of said fittings, a spreader located between the common point of divergence of the strands and the pin of eachtier and adapted to so space the strands of said tier that those portions of the strands between the spreader and the pin are in substantial parallelism, inserts in the slots fitted between the pin and the outer end wall of each slot, and means for clamping all of the fittings in said tier in mutually spaced relation on the pin including annular spacing members on the pin and overlapping the inserts, one of the an-- nular members consisting of a collar disposed between said links and composed of two diametrically separated parts.

4. In a supporting element for a suspension bridge, a" cable comprising a plurality of strands diverging from a common point, a fitting on the end of each strand provided with an elongated slot, a plurality of links arranged in tiers, the links of each'tier being provided near their ends with aligned holes and also lying in a plane passing through said common point of divergence, a

pivot pin passing through the aligned holes in the linksof each tierand also through the elongated,

5. The combination with an anchorage, of a pair of transversely alined spaced converging anchorage elements secured to said anchorage and provided with horizontal transversely alined holes, a pair of parallel links located between said converging elements and provided with transversely alined holes at one end, a pin extending through the holes in said links and said elements, means for holding said links on said pin in planes parallel to a plane intersecting the angle between said converging anchorage elements, a plurality of transversely arranged cables, a socket, for each cable, and horizontal pivot means between said sockets and said links.

6. The combination with an anchorage, of a pair of transversely alined anchorage links pivoted on said anchorage, a plurality of transversely alined strands, a socket secured to each strand and overlapping said links, said overlapping portions of the links and sockets having transversely alined apertures, a pivot pin extending through said apertures, means for holding saidsockets in spaced parallel relation, and a spreader located ,forward of said sockets for spacing said strands the same" distance apart as they are spaced by said sockets.

7.,The combination of' a pair of transversely spacedparallel anchorage links, a plurality of transversely spaced strands, asocket secured to each strand having a reduced shank portion overlapping the ends'of said links, said overlapping portions, of the links and shanks having alined apertures, a pivot pin extending through said apertures, the apertures in said shanks being elongated longitudinally of the shanks whereby shims may be inserted between the end walls of said latter apertures and the-pivot pin, the distance between said links and the transverse width of said shanks being such that the shims may be inserted within said apertures by passing them between said shanks, and a spacer adapted to be mounted on said pivot pin between and in engagement with said shanks to hold said shims in place.

8. The combination of .a cable, an anchorage,

an end fitting for each strand of the cable, the

strands of said cable being splayed to accommodate said end fittings, and being arranged in a plurality of vertical tiers each of which includes a plurality of strands, a pair of links for each tier of strands, a horizontal pivot between each pair of links and the anchorage, and a horizontal pivot connecting the end fittings of each tier of strands to the corresponding pair of links, the pivots between said pairs of links and the anchorage extending along a line inclined to the vertical and toward the anchorage, whereby the links of the upper tiers may be swung out of position to provide for access to the endfittings of the strands of the lower tiers.

9. The combination of a cable comprising a plurality of strands, an anchorage, a plurality of vertically spaced pairs of links, horizontal pivot connections between said links and said anchorage, the strands of said cable being splayed and being arranged in a plurality of tiers corresponding in number to the plurality of pairs of links, the strands of each tier lying in a single plane, sockets on the ends of said strands, and horizontal pivot connections between the sockets of the strands of each tier and. the corresponding links.

10. The combination of a cable, an anchorage, a plurality of vertically spaced pairs of links, horizontal pivot connections between said links and anchorage, the strands of said cable being splayed and being arranged in a plurality of tiers corresponding in number to the pluralityof pairs of links, sockets on the ends of said strands, horizontal pivot connections between the sockets of the strands of each tier and the corresponding links whereby the links may adjust themselves to the direction of the corresponding tiers of strands, and spreaders located between the sockets and the splaying point spacing the strands of each tier the same distance apart as they are spaced at their connection with said sockets.

11; In a construction of the character described, the combination of a cable, a splay member on said cable through which the strands of the cable extend and from which they diverge, a socket for each strand, means pivotally supporting said sockets and strands in tiers, and a spreader for the strands of each tier located between the sockets and the splay member at a point close to said sockets, spacing the strands apart at the same distances as at their point of connection with the sockets.

12. In a construction of the character described,

the combination of a cable, a splay member secured to the cable and from which the strands of the cable diverge, said strands being arranged in a plurality of vertically spaced tiers, each tier comprising a plurality of strands, means for connecting the strands of each tier together to fix the angle of convergence between said means and said splay member, a socket for each strand, an anchorage member, a plurality of links for each'tier of strands, means pivotally connecting on a horizontal pivot the'sockets of the strands of each tier to said links,- and means connecting the links of each'tier on a horizontal pivot to said anchoring means, whereby the links and sockets of each tier may aline themselves with the corresponding strands and change their converging relation with respect to the sockets and links of the other tiers.

13. The combination with an anchorage, of a plurality of non-parallel strands, means securing each strand to said anchorage, and means supported by said strands spacing and arranging said strands tocorrespond to the spacing and arrangement of said securing means whereby said strands assume a parallel relation between said last and 10 first mentioned means.

LEON S. MOISSEIFF.

FREDERICK LIENHARD. 

